Deduplicated Media Storage, Tag Nav and Editing, XHTML-IM, and more

* Content Addressable media storage based on SHA-256 for deduplication
* Tag navigation UI when searching contacts
* Allow editing tags on contacts
* Do not show double notificatin during dialler-integration call
* Allow export/backup of an account where localpart is a large number
* Allow retracting messages
* Dump logs after every call (to make debugging easier)
* Allow keeping data on uninstall (to make switching builds easier)
* Starting private group with @cheogram.com JIDs asks if you want a group text
* New vector chat bubbles (thanks Adaoh!)
* New onboarding screen, beginnings of eventual flow
* Render XHTML-IM including inline media if it is Bits-of-binary
* Performance improvement for low-power devices during startup
* Fix race condition on legacy bookmark sync
* Allow long press to copy any link in a message, not just the first one
-----BEGIN PGP SIGNATURE-----

iQIzBAABCAAdFiEEWeaCw+rzmiEMpzU00RwpEc5RnN4FAmNgDvoACgkQ0RwpEc5R
nN6vzQ//Tor2rJGH9/To6cWkw3MpzQIoT2bBWQs1wT3sHNgDuRpYAdKvMTwO9m19
8408nPNs6LVfmuXT3YkRrxLsGV22TaL1s8vM6MB7uAM3XMXPoVtn+SDT/JXC9yxz
0tlQLVzYYMEzyYGjXPHzmIseP1sDTQ8TNxKfHkjxpQP25dTy0IC3L5B0AENZ4pvF
K8qmYgEtNT5lmKszZN/eTP/9u1XqWCfIyItS+KVRYRd5plF7iaLeeT8Uf2bib1Nt
7b3E++ldPRqMM0ELwEfEqsVg+uCuuJMehD5Kt09xIQhuNwirq06lwAKxyPw/vstW
By8MnZOIEH9uKizwDuGuwgFknTgdPrLfzadUg37p/Dp/wnQbaQo5tDIl2oDr5CzF
rhGjpqLc7K7nFO2nr4CJbaWUIOkxAZitUwmUJhwS0nMLtZYrOplj9PcANiMoKA7A
OAaBvb7ydt2YXxKK8iW1kQNXwoDc2KTZMHNfnNUzlQQqJ15FC4ANf9kS64KUIW/q
7VJtSp96du026VuybXodF//6FQcQPbaZ/UfkdZRJLMY29UxTqLZq7EhtTOz0Eivk
rDvrJLdVouYw2uvR+8E5XbYSr3924aG7IiFYXRupQ1rAk3riEJodpKl+qf+RHg3g
nzB4XKMvPHlWBbLALmaVpqt0mSC1ItcCcVTMEdZVlfwsrxPex4c=
=yQY7
-----END PGP SIGNATURE-----